The present invention generally relates to video signal reproducing apparatuses having a noise reduction circuit, and more particularly to a video signal reproducing apparatus having a noise reduction circuit for reducing noise within a reproduced video signal by use of the field correlation in an input video signal by employing in a feedback path thereof a one-field delay circuit having a band narrower than the band of the input video signal.
Conventionally, in an apparatus for recording and reproducing a video signal on and from a recording medium such as magnetic tape, a noise reduction circuit is provided in a reproducing system to reduce noise within a reproduced video signal. The noise reduction circuit reduces the noise within the reproduced video signal to such an extent that the noise in a reproduced picture is permissible from the practical point of view. Various types of noise reduction circuits have been proposed. As one type of a conventional noise reduction circuit for reducing the noise within the reproduced video signal, there is the so-called recursive type field correlation noise reducer which comprises a one-field delay circuit in a feedback path thereof and reduces the noise within the reproduced video signal by use of the field correlation in the video signal.
As will be described later on in the specification by referring to drawings, a digital memory circuit, an analog shift register or the like is conventionally used for the one-field delay circuit within the recursive type field correlation noise reducer. However, when the digital memory circuit, the analog shift register or the like is used for the one-field delay circuit, the recursive type field correlation noise reducer becomes expensive because of the need to reserve the transmission band of the reproduced video signal. As a result, the cost of the recording and reproducing apparatus as a whole becomes high, and the use of such a one-field delay circuit in a video signal recording and reproducing apparatus for home use is disadvantageous because of the demand to manufacture the video signal recording and reproducing apparatus for home use at a low cost.